OBJECTIVE The goal was to examine in detail the mechanisms of significant scald burns among children <5 years of age, to discover insights into prevention. METHODS Medical records for children <5 years of age who were admitted with scald burns between January 1, 2002, and December 31, 2004, were identified through the University of Chicago Burn Center database. Demographic data and details of the circumstances and mechanisms of injury were extracted from the medical records. RESULTS Of 640 admissions to the University of Chicago Burn Center during the 3-year study period, 140 (22%) involved children <5 years of age with scald burns. Of the 137 available charts reviewed, 118 involved unintentional injuries. Of those unintentional injuries, 14 were tap water scalds and 104 were non-tap water scalds. Of the non-tap water scalds, 94 scalds (90.4%) were related to hot cooking or drinking liquids. Two unexpected patterns of injury were discovered. Nine children (8.7%) between the ages of 18 months and 4 years were scalded after opening a microwave oven and removing the hot substance themselves. Seventeen children (16.3%) were scalded while an older child, 7 to 14 years of age, was cooking or carrying the scalding substance or supervising the younger child. CONCLUSIONS Current prevention strategies and messages do not adequately address the most common mechanisms of scald injury requiring hospitalization. Easy access to a microwave oven poses a significant scald risk to children as young as 18 months of age, who can open the door and remove the hot contents. An engineering fix for microwave ovens could help protect young children from this mechanism of scalding. Involvement of older children in a subset of scald injuries is a new finding that may have prevention implications.